Method of flanging sheet metal can bodies



Dec. 7, 1943. J. coYLE' ,METHOD OF FLANGING SHEET METAL CAN BODIES FiledMay 7, 1942 Patented Dec. 7, 1943 METHOD OF FLANGING SHEET METAL CANBODIES John Coyle, Baltimore, Md., assignor to Continental Can Company,Inc., New York, N. Y., la corporation of New York Application May 7,1942, Serial No. 442,072

- 2 Claims.

The invention relates to new and useful improvements in a method ofanging sheet metal can bodies, having a side seam with solder-bonded lapsections at the ends thereof.

One of the usual methods of hanging can bodies, consists in subjectingthe formed can body to a Hanging die which is shaped so as to expand androll the edge portion of the can body outwardly into a flange which liesin a plane substantially at right angles to the longitudinal axis of thecan body. This produces a curved section in thercan body which joins theflange to the body portion of the can. The radius of this curvature issubstantially uniform throughout the circumference of the can bodyexcept in the region of the side seam where the walls of the can bodyare lapped and solder-bonded together. During flanging thesesolder-bondedv sections resist the flanging die so that the curvature isoften on a greater radius, and this interferes with the forming of atight seam all the way around the can body when an end is securedthereto. When the body is die-shaped from cylindrical form into aflanged end after solder-bonding, the solder is strained at the sideseam due to the expansion of the metal to form the flange, and thisstraining of the solder-bond sometimes causes the body wall which mergesinto the flange in the region of the lap sections is curvedsubstantially on the same radius as the body wall in other regions.

A further object of the invention is to provide a method of hanging acan body, wherein the curvature of the body wall which merges into theange in theregion of the lap sections is preformed to a large extentbefore the solder-bonding takes place, so as to reduce the strain on thesolder-bond during die shaping of the body wall in the final flangingoperation.

A still further object of the invention is to provide a method offianging can bodies wherein the body Wall in the region adjacent thesection from which the flange is to be formed and in the region of thelap sections is curved inwardly so as to reinforce and stiffen theportion of the can body through the side seam from one side of the canbody to the other.

These and other objects will in part be obvious and will in part behereinafter more fully disclosed.

In the drawing which shows a can body of the lock and lap seam typeanged by my improved method,

Figure 1 is a View showing a portion of a can body having the hooksinterlocked preparatory to bumping the side seam.

Fig. 2 is a View similar to Fig. 1 after the joined edges have beenbumped preparatory to solderbonding the same.

Fig. 3 is a sectional view on the line 3 3 of Fig. 2 and showing inbroken lines the formed flange.

' Fig. 4 is a sectional View on an enlarged scale through the Spline andthe hammer showing the seam in its nal bumped condition.

Fig. 5 is a view showing more or less diagrammatically a portion ofthedie for forming the flange partially entered into the can bodypreparatory to the flanging operation. Y

Fig. 6 is a View similar to Fig. 5 but sho-wing the flanging operationas completed.

Fig. '7 is a diagrammatic view showing the reinforcing rib extendingacross the body wall in the region of the side seam, Vthe view beingVtaken substantially on the line 1-1 of Fig. 2.

The method will be described as applied to the ange of a can body havinga lock and lap side seam. This type of can body is well known and onlybrief reference is necessary to the features of construction.

The can body section l is joined to the can body section 2 by a sideseam which includes hooks which are engaged with each other. These hooksterminate short of the ends of the can body so that there are lapsections only in the region where the flange is to be formed. As viewedin Fig. 1, the can body is seen from the'outside of the body and theouter lap is shown at 4 in full lines, while the inner lap is shown at 5in broken lines.

The can body is formed in cylindrical shap about a horn and the hooksare interlocked after which they are bumped to bring them into verytight and intimate contact with each other. This is accomplished by abumping iron or hammer which is brought into contact with the outer faceof the can body in the region of the interlocked hooks. The seam isbumped against the spline which is located in the horn. In Fig. 4 of thedrawing a portion of the spline 6 and the bumping iron o'r hammer l areshown. In carrying out my improved method the spline is provided Wth arecess 8 which extends across the spline from one side thereof to theother. The bumping iron or hammer is provided with a curved `rib 8 whichis opposed to the recess 8.

When the seam is bumped the body wall in the region of the hooks and thelapped sections adjacent the hooks will be curved inwardly, thus forminga rib on the inner wall of the can body which extends across the sideseam and into the can body wall adjacent the side seam. This ribreinforces the body wall and greatly strengthens the same so as toprevent any hinge-like action on the seam formation which is likely toOpen the seam.

The spline 6 is also provided with a recess I which is curved on aradius conforming substantially with the curvature of the body wallmerging into the flange after the Vhanging operation. This curving ofthe body wall is limited substantially to the region of the lapsections. The hammer 'I is provided with a rib II which is curved toconform to the curvature in the recess, and during the bumping operationthe lap portions of the side seam are curved inwardly as indicated inFig. 4 of the drawing.

The bridging member formed during the bumping operation through thecooperation of the rib 9 on the hammer and the groove 8 in the spline isindicated at I2 in the drawings. This rib is substantially straight andis in a sense a chord to the curvature of the cylindrical body. As shownin Figs. 2 and 7 the bridging rib extends through the side seam from oneside of the can body to the other side. This rib is formed before thecan body is solder-bonded. The solder-bonding of the seam is not shownin the drawing, as it is likely to confuse the same, but it isunderstood that when the sfide seam is solder-bonded, the solder willhow into the side seam throughout the limits thereof and join thecontacting metal parts together.

During this bumping operation the rib II on the hammer cooperating withthe recess I0 formed a curved portion I3 in the region of the lapsections, which curved portion is shaped so that it conformssubstantially to the curved portion I4 which joins the finished harigeI5 to the body wall. This curved portion I3 extends from a point I6 to apoint II. I'I to the end of the can body the body wall is expanded intothe harige. The hanging die used for forming the flange on the can bodyis indicated at I8. This hanging die has a portion I8a extending downinto the can body below the rib I2 and is of such shape as not to deformthis rib. It also has a portion |81) which is dimensioned so as tocontact with the inner surface of the bead I3. 'I'he curvature of thebead I3 from the point IB to the point II is closely approximated to thecurvature of the hanging die from the point I8c to the point I8d, seeFigs. and 6. When the die therefore is forced down into the can body theupper end of the can body will be expanded and forced outwardly to formthe harige. The beaded portion I3 will swing about the point I6 more orless as a hinge, for the reason that the curvature of the portion I3approximates the curvature of the die which contacts therewith as thedie moves on down for the hanging operation. In other words, thisportion of the can body in the region of the lap sections has apreformed curve similar to the curve which joins the flange to the bodywall, and it is moved outwardly during this hanging operation. As statedabove, the hanging die when inserted into the can body expands the endof the can body into a flange and at the same time it positions thepreformed curved portion in the lap section so that it merges From thepoint r into the hange on substantially the same curvature as otherportions of the body wall. This shaping of the body wall took placebefore the solder-bonding of the lap sections, and this preforming orcurving of the body wall in the region of the solder-bonded lap sectionsgreatly facilitates the expanding and shaping of the can body to formthe harige without undue strain on the solder-bond.

It is well known that the grain of the metal forming the can body whichis curved around a horn, extends in the general direction of thecurvature of the body, and that it is parallel with the end edges of thecan body. However, when this section of the side seam is bumped so as toprovide the curved portion I3 the grain in the curved portion will bechanged so that it extends lengthwise of the seam and therefore A theshifting of this curved portion I3 and whatever reshaping is necessaryto provide the flange is aided by this change in the grain of the metal.

From the above it will be apparent that three things have beenaccomplished in my improved method of hanging, al1 of which cooperate tothe reducing of the strain in the solder-bond during hanging and theforming of a flange wherein the curved portion of the body wall merginginto the flange is of a substantially uniform radius in the region ofthe side seam, as well as at other points in the circumference of thecan. One of the features is the pre-shaping of the metal in the lapsections prior to solder-bonding so as to facilitate the curving of thebody wall in this region during hanging without undue straining on thesolder-bond. Another feature is the precurving of this section of theseam prior to solder-bonding so as to facilitate the forming of theflange so as to have a uniform curvature throughout to aid in theseaming of the end of the body in a very tight uniform seam. The thirdfeature is the forming of the reinforcing rib where the lap sectionsjoin the hook sections of the seam. This reinforcing rib extends acrossthe seam transversely thereof and extends into the body wall fromoneside of the can body to the other. This reinforcing rib stiffens Athecan body so as to prevent the seam from opening up by the hinging actionof one of the hook sections on the other and the rupturing of thesolder-bond. This not only aids in the'preventing of the rupturing ofthe solder-bond during packaging, but it also prevents rupturing of thesolder-bond during storage of hanged can bodies prior to the seaming ofan end thereon. While a reinforcing rib is shown located at the junctionof the hooks and the lap sections of the seam, it is understood thatreinforcing ribs may be placed at other points along the side seam.

While the method has been described as ap,- plied to a can body of thetype wherein the side seam has interlocked hooks and lap portions at theends thereof, it is to be understood that my improved method of hangingmay be equally applied to a side seam wherein the edge portions arelapped throughout the entire length of the side seam.

I claim:

1. The method of hanging sheet metal can bodies having a side seam withsolder-bonded lap sections at the ends thereof, consisting in bumpingthe lap sections of the side seam on a line parallel to the edge of thebody and in the region where the lap sections are to be expanded andcurved outwardly so as to merge into a flange, for curving said lapsections inwardly ona line of curvature conforming substantially to thecurvature of the body wall merging into the ange after anging,solder-bonding the side seam, and subjecting said can body to a flangingdie for expanding the end of the can body into a flange and positioningsaid preformed curved portion in the lap section so that it merges intothe flange on substantially the same curvature as other portions of thebody wall.

2. The method of flanging sheet metal can bodies having a side seam withsolder-bonded interlockedhooks and lap sections at the ends thereof,consisting in bumping the lap sections of the side seam on a lineparallel to the edge of the body and in the region where the lapsections are to be expanded and curved outwardly so as to merge into aflange, for curving said lap sections inwardly on a, line of curvatureconforming substantially to the curvature of the body wall merging intothe flange after anging, also bumping the side seam in the regions wherethe ends of the hooks terminate for curving the same inwardly to form areinforcing rib extending across the side seam from one side of the bodyto the other, solder-bonding the side seam and subjecting the can bodyto a Hanging die for expanding the end of the can body into a flangeandrpositioning said preformed curved portion in the lap section so thatit merges into the flange on substantially the same curvature as otherportions of the body wall.

JOHN COYLE.

